Variable stroke hand pump



' O. M. SUMMERS 2,423,162 VARIABLE STROKE HAND PUMP July 1, 1947.

Filed July 5, 1943 INVENTOR OTTO M. SLAMEQS BY M & My

ATTORNEYS unit is gradually a hand operated Patented July 1, 1947 UNITED mm PATENT OFFlCE.

, 2,423,162 VARIABLE STROKE HAND PUMP Otto M. Summers Mount Gilead, Ohio, assignor to II-P-M Development Corporation, a corporation of Delaware Application July 5, 1943, Serial No. 493,507 3 Claims. (Cl. 10338) This invention relates and in particular to hand operated hydraulic Dumps.

An objector the invention is to provide a hand increased in proportion pressure developed by the a hand actuated pumping unit that is a self contained mechanism in the reservoir for the single structure.

A still further object of the invention is to provide a hand operated pumping unit-for producing hydraulic pressure that is capable of delivering a large volume of hydraulic fluid at a relative low pressure and which volume delivery is gradually reduced by the pumping mechanism as the pressure is increased on the delivery side of the pumping mechanism.

Another object of the invention is to provide a hydraulically operated manually actuated that the pumping unit and same is contained within a to pumping mechanisms lever over the pumping any 01' the foregoing Still another object of the invention is to provide a hand operated pumping mechanism for producing hydraulic pressure in accordance with objects wherein the volume of fluid delivered by the pump is relatively large as long as the pressure against which the pump is operating is relatively low, but as the pressure increases the delivery of the hand operated pump will fall off so that whenmaximum delivery of pump pressure is being developed by the pump there will be the smallest volume delivery from the pump to meet the final high pressure require:

. ments of a mechanism actuated thereby, but at pumping unit in accordance with the foregoing object wherein the lever for actuating the pumping unit is gradually shortened so that the mechanical advantage of the lever over the pumping creases.

producing hydraulic pressure wherein the discharge pressure developed by the pump is used to move the lever mechanism that operates the pump so as to reduce the centers between the lever actuating mechanism and the pumping unit in response tothe increase in pumping pressure developed by the pump whereby to reduce the volume of fluid discharged by the pump andmaintain the power requirement pump substantially constanth It is another objectof the invention to provide hydraulic pump in accordance with anyof the foregoing objects wherein the point at which the lever actuating mechanism the pump is adjustably regulated.

begins to increase itsmechanical advantage ove increased as the pressure in-.

for actuating the objects that is particularly this time the mechanical advantage of the manually actuating mechanism is the greatest so that the power requirement is no larger than when the pump was producing the lower pressure.

Still another object of the invention is to provide a piston pump that is constructed as a unit piece of equipment that may be inserted into a supporting mechanism and be actuated by any lever actuated device; whereby the piston pump mechanism may be removed and replaced at will without disassembling the entire pumping mechanism forreplacement or repairs.

Another object of the invention is to provide a hand operated pump for producing hydraulic pressure in accordance with any of the foregoing adapted for use in actuating the small services of an aircraft.

Further objects and advantages will become apparent from thedrawings and the following v description.

In the drawings:

Figure 1 is a cross-sectional view of the hand operated hydraulic pump of this invention shown in diagrammatic association with a retractable aircraft landing apparatus,

Figure 2 is a somewhat similar illustration of the arrangement of the hand operated pump as it would be'placed in association with the pilot's seat of an aircraft.

In this invention the pump consists of a main reservoir chamber l0 that provides the supporting member for the pumping mechanism. The reservoir chamber III has an internal chamber I I that receives a body of hydraulic 'fiuid I2 adapted to be pumped by the pumping unit l3.-

The reservoir chamber II has an opening I in the top wall thereof adapted to receive the piston pump unit l3 for insertion therethrough.

The piston pump unit [3 consists of a cylinder The upper edge portion the shoulder l9 and the bottom surface of the recess formed by the enlarged bore 28.

The head portion iii of the piston plunger i1 is hollowed out to form the recess 22 in which there is positioned a hardened metal ball 23 that is supported on a plurality of smaller balls 24. of the chamber i8 is flanged inwardly as indicated by the flange portion 24 in order to hold the hardened metal ball 23 in position within the cage formed by the recess portion 22.

The piston plunger i1 is provided with a plurality of grooves 25 around the portion thereof that reciprocates within the cylinder bore M to i provide an oil seal and thereby prevent leakage of hydraulic fluid upwardly around the piston to the external portion of the reservoir chamber l8.

The cylinder i is provided with 1 or more check valves 28 that consist of a body or cage member 21 enclosed within a recess portion 28 in the cylinder i5 and sealed thereto by means of a resilient seal member 29. A fluid passage 38 is provided in the cage member 28 andis adapted to be closed by means of a ball check 3| that is spring pressed against a seat provided by the passage 38 by means of the spring member 32. As illustrated in the drawing two of these check valves 26 are provided for regulating the flow of hydraulic fluid to the cylinder bore I8 through the passage 33. These check valves open toward the cylinder bore l8 when the piston plunger 11 moves in an upward direction, whereby the check valves 26 act as suction valves for the piston plunger H.

A discharge check valve 34 is provided in the bottom wall 35 of the cylinder l5, this bottom wall portion 35 has a threaded portion 38 that is adapted to be threaded into a threaded opening 31 in the bottom wall of the chamber il whereby to hold the pumping unit l3 in position within the chamber H and with the flange 38 on the cylinder IS in engagement with the top wall of the reservoir chamber l8.

The check valve 34 consists of a ball check member 38 that is retained within a bore 39 that communicates with the cylinder bore l8 by means of the passage 48, the ball check 38 being retained on the seat formed by the passage 48 by means of the coiled spring 4|.

The discharge port 48 and the check valve 38 controls the flow of fluid under pressure from the cylinder bore III as forced therefrom by the piston plunger l1, and communicates with a discharge pressure passage 43 that conducts fluid under pressure to the pressure line 44 that condescribed.

The actuating lever for the piston pump l3 consists of a lever member 45 mounted by means of a pivot head 41 of'a piston plunger. The piston plunger 48 is substantially smaller in diameter than the piston head 41 and is slidably positioned within a cylinder bore 49 provided in the chamber support member l8. The piston plunger member 48 is provided with a plurality of annular rings 58 around the same that retain oil therein and thus prevent from seeping past the piston plunger 48. A wear plate 5| is secured to the actuating handle 45 by means of the cap screws "and is adapted to engage the large ball 23 of the piston pump u it that is pivotally pin 48 upon the high pressure fluid 4 l3 for actuating the piston plunger l'i when the actuating handle is pivoted about the pin 86 in a stroking movement.

The cylinder 49, or the end chamber thereof communicates with the high pressure discharge port 43 from the pumping unit l5 by means of the passage 56.

A retaining guide rod 51 is provided for enag ng the head 41 upon which the lever arm cs is pivoted for guiding the same when it reciprocates along the system reservoir chamber i8 toward the piston pump 53.

A stud 58 extends upwardly from the piston head 41 and has an eye 59 therein against which the head 88 in the end of a rod 8! rests, a spring 82 being provided with an internal bore 83 provided in the reservoir housing l8 and having one end thereof against the bottom wall of the bore 63 and the opposite end against a flanged collar member 64 threaded upon the end of the rod 6|, whereby the head 88.0n the rod BI is retained against the eye 58 of the stud 58 to thereby normally hold the head 41' in position as illustrated in the drawing of Figure 1'. The spring 83 therefore opposes movement of the head 41, and pressure from the discharge passage 83 enters the end chamber 55 of the cylinder 49 to urge the piston plunger 48 in a leftward direction as viewed in Figure 1.

A transverse passage W8 is provided in the piston 48 that is adapted to cooperate with a passage I8| in the chamber housing l8 whereby to control the maximum forward stroke of the piston 48 due to the application of pressure in the end chamber 55.

As illustrated in Figure 2 of the drawing the pumping unit of this invention is adapted for use on an aircraft and is positioned adjacent the pilot's seat so that he can use the hand pump in raising or lowering the retractable landing gear of the aircraft or to provide hydraulic pressure for operating other serviceson the aircraft as desired. The pumpingunit would preferably be placed adjacent the floor of the aircraft with the handle 18 being positioned'along side pilot seat 1|, so that he could grasp the handle and I move the same upwardly and downwardly to renects to a service of an aircraft to be hereinafter the jack under low service lines 92 and ciprocate the handle and thus provide stroke on the piston pump unit l3.

As illustrated in Figure 1 the hand operated pumping unit of this invention is'adapted to supply fluid to either end of a hydraulic jack 98 that is provided for operating, aretractable landing gear 9| provided on an aircraft. The hydraulic jack 98 hasthe pressure service lines 92 and 93 that are connected to a fluid flow control valve 94. The pressure discharge conduit 44 from the pressure line 43 of the pumping unit I3 is connected to the flow control valve so that pressure fluid can be delivered into either of the 93 supplying the service jack line 95 is connected to-the I fluid that is being discharged from the jack 98 when pressure fluid is being supplied to one side thereof. Thedischarge line 95 connects with the reservoir chamber II to return hydraulic fluid to the reservoir chamber after it has been used or served its purpose in the jack 88.

When operating a hydraulic surface such as the jack 98, it is particularly desirable that a large volume of hydraulic fluid be supplied to pressure ginning to retract the landing gear mechanism 1. 50 t e aircraft. This provides for rapid re- 98. Also, a-return valve 94 so as to return when the jack is betraction of the landing gear. As the landing gear begins to approach its final position in the aircraft as illustrated in the dot-dash line shown in Figure 1, the total volume of fluid required to operate the jack becomes less, but the pressure of the fluid is considerably higher. Therefore at this time it is possible to supply a lesser quantityof fluid to the Jack 90 but at a higher pressure in order to complete the retraction of the jack. 1

If a standard type Press pumping hand operatedpumping mechanism was used in this particular construction and arrangement the pump handle would operate relatively easy at the beginning of the retraction period but it would take a tremendous effort on the partof the operator to operate the pump when the high pressure developes at the end of the operating period.

Therefore it is an object of this invention to pro-- sure that is being developed by the pump. In

order to accomplish this feature the leverage between the pivot 46 and the ball 23 is gradually reduced by moving the pivot pin 43 toward the vertical center-line of the ball 23, as the-pump pressure increases thereby increasing the mechanical advantage of the hand lever over the pumping unit l3 so that a constant effort applied upon the handle by the operator will opa pressure in this line should it become desirable to do so. A suitable hand lever 85 can be provided for operating the actuated member 83.

While the apparatus disclosed and described herein constitutes a preferred form of the invention, yet it is to be understood that the device is capable of mechanical alteration without departing from the spirit of the invention, and

that all such modifications as fall within the slides on said piston first-named resilient means erate the pumping unit to produce any desired pressure for operating a service.

In order to vary the leverage between the piston 46 and the ball 23, the high pressure discharge from the pumping unit I3 is discharged through the conduit 43 and the conduit 58 into the end chamber 55 of the cylinder 49, so that as the pressureincreases in the chamber 55 it will overcome the resistance of the spring 62 and thereby force the piston 48 in a leftward direction, thus moving the head 21 and the pivot 46 in a leftward direction toward the ball 23.

It will therefore become apparent that the stroke of the pump will be decreased as the pivot 46 moves in a leftward direction, and in fact can be brought to a substantially neutral position if the pivot of 46 is placed directly in a vertical line over the ball 23. .At the same time, the hand lever 10 is gaining a mechanical advantage over the pump I3 so that the pressure being de-,

veloped by the pump l3shall not require any greater operating eifort on the part of the operator when producing a high pressure than when it is producing a low pressure.

To adjust the point at which the pivot '46 begins to move in the leftward direction, the tension of the spring 62 is controlled by the initial compression placed thereon by. adjusting the collar 54 upon the rod 6|.

A shut-off valve rod 80 is provided in the passage 43 and has a ball 8l' on the end thereof adapted to cooperate with the fitting 82 to form a valve. The opposite end of the'rod 80 is envgaged by an actuating member 83 that is threaded in the fitting member 84 secured within the wall of the reservoir chamber I0. Rotation of the member 83 will force the ball 8| against the fitting 82 and thereby close the discharge line 44 and retain pressure therein in order to hold scope of the appended claims are intended to be opposite end of said lever being free, and resting freely on said flrst-namedpiston, and being actuated to reciprocate said piston, means for supporting said one end of said lever adjacent to said pivot means and permitting free sliding movement of said lever whereby said piston lastnamed and said lever have a straight line movement with relation to each other as said lever for holding said pivot means in a predetermined .normal position to obtain a'maximum spacing between said pivot means and the fulcrum of said lever means on said piston, and means for conducting fluid under pressure from the discharge side of the pump to said second piston means to actuate the same to overcome said resilient means and move said pivot means toward said piston to shorten the leverage between said pivot means and the fulcrum of said lever on said piston in response to the pressure increase of said pump to increase the stroke of said lever for maintaining the same stroke of said piston.

2. A hydraulic pump comprising a cylinder and a piston reciprocable therein, a lever for reciprocating said piston and engaging the same intermediate the ends of the lever to form a ful crum for said lever and to actuate the piston through the said fulcrum, a second reciprocable piston means, pivot means connecting one end of said lever to an end of said second piston means, the opposite end of said'lever being free,

and being actuated to reciprocate said piston,

means for supporting said one end of said lever adjacent to said pivot means and permitting free sliding movement of said lever whereby said piston last-named and said lever have a straight line movement with relation to each other as said lever slides on said piston first-named, resilient means for holding said pivot means in a predetermined normal position to obtain a maximum spacing between said pivot means and the fulcrum of said lever on said piston, and means for conducting fluid under pressure from the discharge side of the pump to said second piston means to actuate the same to overcome said resilient means and move said pivot means toward said piston to shorten the leverage between said pivot means and the fulcrum of said lever on said piston in response to the pressure increase of said pump to increase the stroke of said.

lever for maintaining the same stroke of said pissaid lever slides on curved and another portion beyond said curve forming a handle.

3."A hydraulic pump comprising a cylinderand a piston reciprocable therein, a lever for reciprocating saidpiston and engaging the same intermediate the ends of the lever to form a tulcrum for said lever and to actuate the piston through the said fulcrum, a second reciprocable piston means, of said lever to an end of said second piston means, the opposite end of said lever being free, and resting freely on said first-namedpiston, and being actuated to reciprocate said piston, means for supporting said one end or said lever adjacent to said pivo'tmeans and permitting free sliding movement of said lever whereby said piston last-named and said lever have a straight line movement with relation to each other as said piston first-named, resilient means for holding said pivot means in a predetermined normal position to obtain a maximum spacing between said pivot means and the fulcrum of said lever on said piston, and means for conducting fluid under pressure from the discharge side of the pump to said second piston means to actuate-the same to overcome said resilient means and move said pivot means toward said piston to shorten the leverage between said pivot means and the iulcrum of said lever on 1 saidpiston in response to the pressure inpivot means connecting one end I crease of said pump to increase the stroke of said lever for maintaining the same stroke oi said piston, said lever having a portion ofiits free end curved and another portion beyond said curve forming a handle, and passage means nor-.

o'r'ro M. SUMMERS.

REFERENCES orrEn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,649,356 Louis e Nov. 15, 1927 2,070,935 Traut Feb. 16, 1937 2,191,552v Zimmermann Feb. 27, 1940 870,630 Kinsman Nov. 12, 1907 2,183,436 Towler L Dec. 12, 1939 635,258 Lange Oct. 17, 1899 FOREIGN PATENTS Number Country I Date 455,981 France 1913 

